Bump Minimum Version of Cmake

[nosracd]

Recent versions of cmake produce the following warning for LCM:

CMake Deprecation Warning at CMakeLists.txt:1 (cmake_minimum_required):
  Compatibility with CMake < 3.5 will be removed from a future version of
  CMake.

  Update the VERSION argument <min> value or use a ...<max> suffix to tell
  CMake that the project does not need compatibility with older versions.

This PR fixes the warning by bumping the minimum required version of cmake from 3.1 to 3.5.